The study uses standard genetic methodology (linkage analysis) to investigate the distribution of polymorphisms for anonymous genetic markers in families with familial pulmonary fibrosis. The comprehensive genome-wide study, using standard genetic markers, will allow identification of loci which subsequently may prove to contain novel genes that play a role in the pathogenesis of pulmonary fibrosis. Once genetic loci are defined in familial pulmonary fibrosis, candidate genes can be identified on the basis of both positional and functional criteria. Moreover, this approach will provide basic information on high priority loci that will be applicable to the rapidly evolving dense human transcript map for pulmonary fibrosis in families with two or more cases of pulmonary fibrosis.